Advanced Ultra High Performance InP Solar Cells

Indium Phosphide (InP) is a semiconductor compound typically used in solar cells and high speed electronics. InP has a number of performance benefits compared to other III-V materials due to its higher mean and peak saturation velocities, which result in optoelectronic devices with higher frequency. InP solar cells, with a bandgap of 1.34 eV and high absorption levels, have a strong potential of reaching the Shockley-Queisser theoretical efficiency level of approximately 33%. Despite this potential, however, the efficiency levels of InP solar cells have previously been recorded at 21.9%.

Description

Researchers at NREL have developed a method to increase the efficiency levels of InP solar cells to 24.2% in the AM1.5G spectrum and 22.1% in the AMO spectrum. These record-breaking efficiency levels were obtained by reducing non-radiative recombination losses at the absorber layer interfaces to a minimal level by employing dual minority-carrier confinement schemes. In the n-on-p architecture, for instance, a highly-doped front-surface confinement layer is grown on top of the InP emitter layer, creating a potential barrier between the highly-doped surface layer and the lightly-doped emitter. For confinement of carriers from the p-type InP layer, a lattice-matched AlGaInSbAsP alloy is utilized. Additionally, the invention outlines optical-confinement schemes to improve the cell efficiency even further.

The new efficiency levels achieved by the NREL researchers have set a new world record for InP solar cell efficiency and were achieved at 25 degrees C at a one sun intensity level.

Systems and methods for advanced ultra-high-performance InP solar cellsSystems and Methods for Advanced Ultra-High-Performance InP Solar Cells are provided. In one embodiment, an InP photovoltaic device comprises: a p-n junction absorber layer comprising at least one InP layer; a front surface confinement layer; and a back surface confinement layer; wherein either the front surface confinement layer or the back surface confinement layer forms part of a High-Low (HL) doping architecture; and wherein either the front surface confinement layer or the back surface confinement layer forms part of a heterointerface system architecture.